    {:cell-spacing "0"}
 
    [:thead>tr
-    [:td {:width "20px"} "-"]
-    (map #(vec [:th {:width "20px"} (str %)]) (range m/PLAYFIELD-WIDTH))]
+    [:th {:width "20px"} "-"]
+    (map #(vec  [:th {:key (str %) :width "20px"} (str %)]) (range m/PLAYFIELD-WIDTH))]
 
    [:tbody
 

  [nrow rowdata]

  ^{:key (str "r-" nrow)} [:tr
    [:td (str nrow)]
    (map plot-cell rowdata)
    ]
  )


; Plots the playfield, it is a table of size w*h
;

(defmulti plot-cell (fn [data _] (:tipo data)))

(defmethod plot-cell :PESCE
  [data idx]
  ^{:key idx}
  [:td {:class (name (:colore data))}  (str "P" (:energia data)) ] )

(defmethod plot-cell :SQUALO
  [data idx]
   ^{:key idx}
   [:td {:class (name (:colore data))}  (str "<" (:energia data)) ] )

(defmethod plot-cell nil
  [data idx]
  ^{:key idx}
  [:td ""] )


